Ion Irradiation Effects on Ho_2+xTi_2-xO_7-x/2 (x=0, 0.4 and 0.67)

Abstract:

We recently synthesized different composition polycrystalline Ho2+xTi2-xO7-x/2 (x=0, 0.4 and 0.67), which is derivative fluorite compounds known as and pyrochlore phases in Ho3O2-TiO2 phase diagram by using conventional solid state synthesis methods. The samples were irradiated with 400 keV Ne2+ ions at cryogenic temperature (~77 K), using the Danfysik ion accelerator at the Ion Beam Materials Laboratory (IBML) of Los Alamos National Laboratory (LANL). The irradiation fluences in the experiments ranged from 5×10¹⁴-5×10¹⁵ ions/cm². An order-to-disorder (O-D) transformation was observed for α, β and pyrochlore phases, as determined using grazing incidence X-ray diffraction (GIXRD) at an incident angle of 0.25°. The O-D transformation threshold fluence for α phase was found to be noticeably lower than those for β phase and pyrochlore, and the O-D transformation threshold fluence for β phase was the highest. The O-D transformation threshold fluence was found to be coherent with the phase transformation temperature in the Ho₃O₂-TiO₂ temperature-composition (T-C) phase diagram.

• Periodical: Key Engineering Materials (Volumes 512-515)
• Pages: 643-647
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.512-515.643
• Online since: June 2012
• Authors: Yu Hong Li, Yong Qiang Wang, Juan Wen, Valdez A. James, Kurt E. Sickafus
• Keywords: GIXRD, Ho_2+xTi_2-xO_7-x/2, Ion Irradiation, Phase Transformation

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